Open-hearth furnace



july LNE@ R. s. A. DOUGHERTY 1369326 OPEN HEARTH FURNACE Filed May 8. 192,2

by the open hearth process.

Patented July l, 1930 UNITED STATES PATENT OFFICE ROBERTS. A. DOUGHERTY, OF BETIILEHEM, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO OPEN HEARTH COMBUSTION COMPANY, A CORPORATION O F NEW JERSEY OPEN -BEARTE FURNACE The present invention relates to reverberatory regenerative furnaces and particularly tofurnaces of this type designed and constructed for use in the manufacture of steel The object of the invention is to provide a reversible regenerative furnace having a novel and improved end construction in which the throat or'pass'age provided for the introduction of combustible gas into the com- I bustion space and for conducting away gases of combustion has associated therewith means for varying its effective area so that when serving as an inlet for unburned gases the throat may be of relatively small effective area and vwhen serving as an outlet passage for the products of combustion of relatively large effective area so that the combustible gases may be introduced at high velocity and with a blow pipe effect, if desired, and the expanded and highly heated products of combustion may pass off freely.

The means employed for effecting the variation in the eiective area of the throat consists in a damper insertable into the throat preferably through an aperture in the roof of the furnace. This damper is. arranged at an angle to the vertical and transversely of the axis of the throat and slopes downwardly and inwardly toward the hearth.

When the throat is serving as` an outlet pas-V sage for burned gases the damper is prefer-f ably wholly removed but when it serves as an inlet passage the damper may be lowered 'any distance desired. The gases, particularly the air supplied, iiowing toward the combustion space, at the inlet end of the furnace impinge on the inclined rear surface of the Llowered damper and an additional advantage is realized .in that the flow of gas is directed downwardly toward the hearth. The damper accomplishes this function for all adjustments thereofthough of course its influence on the incoming gases is greatest when adjusted to its'lowermost position.

The invention is capable of embodiment in different furnace Vconstructions and oneembodiment is illustrated in the accompanying drawings and below described in detail, by way of example.

In the drawings: Figure 1 is a longitudinal section through a regenerative open hearth furnace having the invention incorporated therein;

enclosed between the roof, hearth and monkeywalls comprising throats through each of which combustible and burned gases are al; ternately passed. Gas uptake flues are indicatedat 15 and air upftake flues at 16, the gas lues having inwardly and downwardly inclined portions 15 terminating in ports 17 in rear of the throats 14, and the air up-takes 16 terminating in ports 18 opening into the furnace end in rear of the throat. The gas ad air up-takes are in'communication at their lower ends with regenerators which are not shown but which may be of the usual type. The end portions of the roof above the air ports are downwardly and inwardly inclined so that the air passing into the combustion space, which may beunder aconsiderable pressure and at a relatively high velocity, is downwardly directed to envelop the stream of gas from the port 16 and force this Ygas toward the hearth. Vertically disposed water conducting pipes or conduits 19 are `provided to cool and protectithe corners of the monkey walls against erosion.

' For regulating the effective area of the hearth. A' motor M connected to the damp- 100 ers by means of a cable 22 may be utilized to raise and lower the same, the cable 22 being passed around a drum 23 arranged to be rotated by the motor, so that they are simultaneously operable. The dampers may be individually operated if desired.

In the operation of the furnace the damper at the inlet end is lowered and the damper at the outlet end is raised as shown in Figure l. Either the gas or air or both may be supplied under considerable pressure if desired so that the flow of gases through the furnace is at a relativel hi h velocity, thus promoting rapiditgy7 o meIting of thev charge. In Figure 1 the dampers are illustrated in the positions which they occupy when the left and end is the inlet end, and it will be seen that the area of the throat has been decreased by the lowering of the damper 20 while at the outlet end the entire throat area is available for the passage of the expanded hot gases so that the draft is unchecked, the air and gas up-takes having sutlicient area to easily conduct away the burned gases passing through the throat. A blow pipe effect may therefore be realized without rapidly burning out the furnace. It will be seen that notwithstanding the extent to which the damper at the inlet end may be lowered it, will always have a tendency to direct the incoming gases downwardly toward the hearth, thereby causing it to burn where the heat is most needed, and protectin the roof.

aving thus described my invention,-what I claim as new and desire to secure by Letters Patent is:

- An end construction for regenerative open hearth furnaces, comprising a laterall restricted throat, guideways in the wa ls at the restricted portion, said guideways extending from the roof part way to the Hoor, and a damper sliding through the roof in the lateral guideways.

In testimony whereof I hereunto affix my signature.

ROBERT S. A. DOUGHERTY. 

